Many existing shelving and rack systems are constructed of one or more poles connected to one or more shelves or racks. In some cases, the shelves or racks can be adjustably connected to the poles at different heights. Also, each pole often includes two or more pole sections that are connected in an end-to-end fashion by pole connector devices or assemblies. Pole connector devices and the poles assembled with such devices are preferably strong, lightweight, easy to assemble (and in some cases, disassemble), and relatively inexpensive. However, existing pole connector devices fail to balance these design considerations well, invariably resulting in pole connector device designs that are lacking in one or more respects. Conventional pole connector devices and assemblies are often unreliable, heavy, slow to assemble and disassemble, expensive to manufacture, and difficult to properly align and adjust.
For example, many conventional pole connector devices include a plurality of pole inserts that are inserted into the ends of pole sections. These pole connector devices are used to connect adjacent pole sections in end-to-end fashion as mentioned above. Such pole connector devices can have one or more exterior threaded surfaces. Many types of pole inserts are die cast, and have threads machined into the exterior surface(s) of the inserts. The threaded pole inserts are threaded into threaded ends of the pole sections to connect the pole inserts to the pole sections and to connect adjacent pole sections together.
Some existing threaded inserts are formed of a single piece or assembly having a separate threaded portion on each end of the insert for threaded connection with an internally threaded pole section. Other threaded inserts are threaded only on one end for threaded connection with a pole section. In such cases, the threaded inserts are inserted into the ends of adjacent pole sections and are then connected together with a fastener to connect the adjacent pole sections. By way of example only, the fastener can be rod threaded on each end. After the inserts are inserted into the ends of adjacent pole sections, one end of this fastener type is threaded into a threaded aperture in one of the inserts. The opposite end of the fastener is then threaded into a threaded aperture in the other insert and is tightened to connect the adjacent pole sections together.
The machining required for threading conventional pole inserts is expensive and can represent a significant part of the cost of a shelving and rack system. Such machining also adds an additional step in the manufacturing process and can significantly add to the time needed to produce a shelving and rack system. Although a number of alternatives exist to machining threads into the pole inserts and pole section ends (e.g., casting or molding threads), each of these alternatives adds significant costs to the manufacturing process in one or more ways, such as through expensive molds and molding machinery, etc.
The use of threaded pole inserts can also add significant time to the pole assembly process, especially when several pole sections and several rack or shelf systems need to be assembled. Such inserts and pole sections can be difficult to thread together, and in some cases may not properly align to form a straight pole. Some pole connections may be used to connect two or more poles in a way that joins the poles in other manners, such as at any angle or in a parallel fashion but not necessarily co-axial. In such cases, threaded connections can be cumbersome and ineffective. If threaded correctly, an insert threads into a pole along a central pole axis extending parallel to the walls of the pole. In some cases, the threads on the insert may become misaligned with the threads of the pole during assembly, causing the insert to become misaligned with respect to the pole axis and result in an unstable pole connection. Such unstable pole connections can be difficult to detect by the assembler. In addition to misalignment problems, the process of tightening the pole inserts into the pole sections during assembly and of loosening such connections during disassembly can be difficult, often requiring significant strength and/or tools. Also, threaded inserts can loosen as a result of rack or shelf use and vibration, resulting in unreliable connections between pole sections.
Other types of pole section connectors do not employ threaded connections to the pole sections. For example, some pole section connectors employ inserts that are received into the ends of the pole sections and are attached thereto by adhesive or cohesive bonding material. Such pole section connectors can be difficult to properly align (while the bonding material sets and/or while the inserts are assembled with the pole sections). It can also be difficult for an assembler or user to detect when the bonding material has failed or is otherwise unsatisfactory for bearing normal loads. In addition, the use of bonding material for pole section connections can make pole disassembly problematic or even impossible.
In light of the problems and limitations described above, a need exists for pole assembly connectors that enable quick assembly and disassembly of rack or shelf poles, can be inexpensively manufactured, are easy to properly align and assemble, and provide a strong and reliable connection between pole sections. Each preferred embodiment of the present invention achieves one or more of these results.